Keithley 199 Instruction Manual page 64

IEEE-488 PROGRAMMING
Step 4: F'mgram Model I99 Operating Modes Step 5: Get Readings from the Model 199
You can program instrument operating modes by sending
the appropriate command, which is made up of an ASCII
letter representing the command, followed by a numeric
parameter for the command option. Table 3-l summarizes
the commands used to select function and range.
Usually, you will want to 0btaj1-1 one or more readings from
the Model 199. In the example program above, a single
reading is requested Andy displayed after each command.
fin other cases, you may wish to program the instrument
configuration at the beginning of ,your program, and then
obtain a whole series of measureme&.
A number of commands can be grouped together in one
string,-if desi?ed.~Also, you must terminate the comrnai~!
or command string with~the X character in order for the
instnunent to execute the commands in question.
The basic reading st+g that the MC&I 199 sends over the
bus is in ASCII characters of the form:
NDCV-123456E+O
If you are using the programming example from Step_3
above, simply type in the command string when prompted
to do so. Some example strings are given below.
where: N indicates a normal reading (0 would indicate an
overflow),
DCV shows the function in effect (iti this case, DC
volts)
F3X select DCA function.
FORZX select DCV function, 3V range.
-1.23456 is the mantissa of the reading data,
E+O represents the exponent.
Table 3-1. IEEE-488 Commands Used to Select Function and Range
Mode
Command Desaiption
Execute X Execute other device-dependent commands.
Function FO DC volts
E
AC volts
Ohms
F3
DC current
F4 AC current
E
ACV dB
ACA dB
Range
DCV AC%' DCA ACA Ohms
ACV dB ACA dB
RO Auto Auto Auto
Auto Auto Auto Auto
Rl 3QOmV 3CGmV 3OmA 30inA 300 R
Auto Auto
R2
3V 3V 3A 3A 3kfl Auto Auto
E
30 v 30 v
3~ ~A
3
A 30 kSl Auto Auto
3ooV.3COV 3A
3
A 3COkQ
Auto Auto
R5
3OOV3OOV 3A 3A 3MQ Auto Auto
R6
3ooV3OOV 3A
3
A 3OMR
Auto Auto
R7
3ooV3OOV 3A
3
A 3COMfI Auto Auto
33